The description of art in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such.
Medical imaging is important and widespread in the diagnosis of disease. In certain situations, however, the particular manner in which the images are made available to physicians and their patients introduces obstacles to timely and accurate diagnosis of disease. These obstacles generally relate to the fact that each manufacturer of a medical imaging system uses different and proprietary formats to store the images in digital form. This means, for example, that images from a scanner manufactured by General Electric Corp. are stored in a different digital format compared to images from a scanner manufactured by Siemens Medical Systems. Further, images from different imaging modalities such as ultrasound and MRI are stored in formats different from each other. Although it is typically possible to “export” the images from a proprietary workstation to an industry-standard format such as “Digital Imaging Communications in Medicine” (DICOM) 3.0, several limitations remain as discussed subsequently. In practice, viewing of medical images typically requires a different proprietary “workstation” for each manufacturer and for each modality.
Currently, when a patient describes symptoms the patient's primary physician often orders an imaging-based test to diagnose or assess disease. Typically days after the imaging procedure, the patient's primary physician receives a written report generated by a specialist physician who has interpreted the images. The specialist physician, however, typically has not performed a clinical history and physical examination of the patient and often is not aware of the patient's other test results. Conversely, the patient's primary physician typically does not view the images directly but rather makes a treatment decision based entirely on written reports generated by one or more specialist physicians. Although this approach does allow for expert interpretation of the images by the specialist physician, several limitations are introduced for the primary physician and for the patient:                1) the primary physician does not see the images unless he/she travels to another department and makes a request;        2) it is often difficult to find the images for viewing because there typically is no formal procedure to accommodate requests to show the images to the primary physician;        3) until the written report is forwarded to the primary physician's office, it is often difficult to determine if the images have been interpreted and the report generated;        4) each proprietary workstation requires training in how to use the software to view the images;        5) it is often difficult for the primary physician to find a technician who has been trained to view the images on the proprietary workstation;        6) the workstation software is often “upgraded” requiring additional training;        7) the primary physician has to walk to different departments to view images from the same patient but different modalities;        8) images from the same patient but different modalities cannot be viewed side-by-side, even using proprietary workstations;        9) the primary physician cannot show the patient his/her images in the physician's office while explaining the diagnosis; and        10) the patient cannot transport his/her images to another physician's office for a second opinion.It would be desirable to allow digital medical images to be viewed by multiple individuals at multiple geographic locations without loss of diagnostic information.        
“Teleradiology” allows images from multiple scanners located at distant sites to be transferred to a central location for interpretation and generation of a written report. This model allows expert interpreters at a single location to examine images from multiple distant geographic locations. Teleradiology does not, however, allow for the examination of the images from any site other than the central location, precluding examination of the images by the primary physician and the patient. Rather, the primary physician and the patient see only the written report generated by the interpreters who examined the images at the central location. In addition, this approach is based on specialized “workstations” (which require substantial training to operate) to send the images to the central location and to view the images at the central location. It would be advantageous to allow the primary physician and the patient to view the images at other locations, such as the primary physician's office, at the same time he/she and the patient see the written report and without specialized hardware or software.
In principle, medical images could be converted to Internet web pages for widespread viewing. Several technical limitations of current Internet standards, however, create a situation where straightforward processing of the image data results in images which transfer across the Internet too slowly, lose diagnostic information, or both. One such limitation is the bandwidth of current Internet connections which, because of the large size of medical images, result in transfer times which are unacceptably long. The problem of bandwidth can be addressed by compressing the image data before transfer, but compression typically involves loss of diagnostic information. In addition, due to the size of the images the time required to process image data from an original format to a format which can be viewed by Internet browsers is considerable, meaning that systems designed to create web pages “on the fly” introduce a delay of seconds to minutes while the person requesting to view the images waits for the data to be processed. Workstations allow images to be reordered or placed “side-by-side” for viewing but again an Internet system would have to create new web pages “on the fly” which would introduce further delays. Finally, diagnostic interpretation of medical images requires the images are presented with appropriate brightness and contrast. On proprietary workstations these parameters can be adjusted by the person viewing the images but control of image brightness and contrast are not features of current Internet standards (http or html).
It is possible to allow browsers to adjust image brightness and contrast, as well as other parameters, using “Java” programming. “Java” is a computer language developed by Sun Microsystems specifically to allow programs to be downloaded from a server to a client's browser to perform certain tasks. Using the “Java” model, the client is no longer simply using the browser to view “static” files downloaded from the server, but rather in addition the client's computer is running a program that was sent from the server. There are several disadvantages to using “Java” to manipulate the image data. First, the user must wait additional time while the “Java” code is downloaded. For medical images the “Java” code is extensive and download times are long. Second, the user must train to become familiar with the controls defined by the “Java” programmer. Third, the user must wait while the “Java” code processes the image data, which is slow because the image files are large. Fourth, “Java” code is relatively new and often causes browsers to “crash”. Finally, due to the “crashing” problem “Java” programmers typically only test their code on certain browsers and computers, such as Microsoft Explorer on a PC, precluding widespread use by owners of other browsers and other computer platforms.
Wood et al. (U.S. Pat. No. 5,891,035) describe an ultrasound system which incorporates an http server for viewing ultrasound images over the Internet. The approach of Wood et al., however, creates web pages “on the fly” meaning that the user must wait for the image processing to complete. In addition, even after processing of the image data into a web page the approach of Wood et al. does not provide for processing the images in such as way that excessive image transfer times due to limited bandwidth are addressed or provide for “brightness/contrast” to be addressed without loss of diagnostic information. In addition, the approach of Wood et al. is limited to ultrasound images generated by scanners manufactured by a single company (ATL), and does not enable viewing of images from modalities other than ultrasound.
FIG. 1 summarizes a common prior art approach currently used by companies to serve medical images to Internet browsers (e.g. General Electric's “Web-Link” component of their workstation-based “Picture Archiving and Communication System” (PACS)). As can be seen in FIG. 1, serial processing of image data “on the fly” combined with extensive user interaction results in a slow, expensive, and unstable system.
Referring to FIG. 1, after a scanner acquires images (Step 100) a user may request single image as a webpage (Step 200) whereby the image data is downloaded (Step 300) to allow the user to view a single image with the single image (Step 400). Steps 1000-1400 result in extensive user interaction which results in the system being slow, expensive and unstable.
While the present invention relates to medical imaging generally, it will be better understood within the discussion of exemplary embodiments directed toward cardiac imaging.